Macro-Parametrics Approach
for CAD Translation to X3D
Yuna Kang, Pranveer Singh Rathore, Soonhung Han
iCAD Lab
KAIST
http://icad.kaist.ac.kr
Contents
•
•
•
•
•
Background
Macro-Parametrics Approach (MPA)
X3D Translator
Experiments
Conclusion
2
CAD Modeling Approach
Protrusion
Extrude
Operation or feature
Protrusion
Extrude
Protrusion
Extrude
Procedural model
Protrusion
Cut
Protrusion
Cut
Explicit model
(B-rep)
Boundary
evaluation
Protrusion
Cut
3
Modeling Approaches
Explicit modeling
Procedural modeling
Representation
B-rep
The sequence of operations (features)
used in constructing the model
Access to geometric
information
Easy
Difficult
Editability
Difficult
Easy
Purpose
Engineering analysis,
visualization
Engineering design change,
design optimization
• Commercial CAD systems support a mixture of two modeling approaches
4
Example: As-Is
Intelligent Model
(Procedural Model)
Dumb Model
(B-rep Model)
T
W
•
T=4.1*W
Current
STEP
File
Lost of design intents (feature, constraints, parametric information)
* From slide file, PDES, Inc
5
Example: To-Be
Intelligent Model
Intelligent Model
(Procedural Model)
(Procedural Model)
T
T
W
•
T=4.1*W
Feature
and
Parametric
Information
W
T=4.1*W
Final goal
– Feature-based or history-based exchange
* From slide file, PDES, Inc
6
Macro-Parametrics Approach(MPA)
• MPA is a methodology of exchange of CAD model data between CAD
systems using macro file
• Macro file contains the modeling operation history of each
commercial CAD system
•
http://www.macro-parametrics.org
Pro/E
CATIA
UG
common
set
Neutral Macro File
Inventor
SolidWorks
7
XML Macro File
CAD model
XML macro file
8
Implementation Team at KAIST
3ds Max
-
UG
H. Lee
I. Kim
UG Macro
D. Kim
Pro/E
S. Lee
SKETCH
-
Post
Abaqus
I. Song
M
A
CATIA
H. Cho
TransCAD
S. Shin
J. Li
M
A
A
A
M
Inventor
H. Kim
Persistent
Naming
(B.C.
I. Song
Kim)
Microstation
J. Hwang
A
RapidForm
G. Cho
A
Tribon/PDMS
M
M
AVEVA
J. Li
SolidWorks
X3D
P. Singh
Y. Kang
M
9
CAD Modeling & Exchange
Polygonal
Representation
(Mesh)
Explicit
model
Final shape
X3D
Others
Features
MPA
Procedural
model
Procedure
Modeling
Commands
Constraints
10
Mesh Processing Pipeline
Facet
High
Resolution
Mesh
Multi-Resolution Mesh
• Mesh Processing Pipeline modified from
Mario Botsch(2006)*
Phase 1. Export Facet data from ACIS kernel
Phase 2. Get the high resolution mesh using
TetGen
Phase 3. Reduce mesh for getting multiresolution using MeshLab
* Mario Botsch, Mark Pauly, Christian Rossl,
Stephan Bischoff, Leif Kobbelt. “Geometric
Modeling Based on Triangle Meshes”,
EUROGRAPHICS 2006 Tutorials, Vienna, Austria,
2006.
11
X3D Translation Scenario
DT: Delaunay Triangulated
12
Test Cases Set I (KAIST)
K1: L-Block
K5: Engine Air-Filter
Housing
K2: Y-Model
K3: Gas Spring
K6: Pneumatics Cylinder
K4: Linear
Sensor
K7: Chisel
13
Test Cases Set II
(ACIS models with complex surfaces)
14
Experiments
15
Test Case : Y-model (KAIST)
Y-model (KAIST) after (a) Phase I (b) Phase II (c), (d), (e), (f) Phase III
16
Test Case : Bracket (ACIS model)
Bracket (ACIS) after (a) Phase I (b) Phase II (c), (d), (e), (f) Phase III
17
Test Cases Set I (KAIST)
High Resolution models after Phase II
18
Test Cases Set II
(ACIS models with complex surfaces)
High Resolution models after Phase II
19
Conclusion
• CAD translation to X3D using Macro-Parametric Approach
• The CAD models of several commercial CAD systems can be
transfer to X3D
• If X3D can contain history information in the future, it is
possible to translate CAD to X3D with history information
also, using Macro-Parametrics Approach
20
Resources for further Information
•
•
•
•
www.macro-parametrics.org
www.tetgen.berlios.de
www.meshlab.org
W3C member resources on www.web3d.org
– “Members only Wiki”  X3D CAD Working Group
– “Documents”  CAD  Macro
21
Thank You
22
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
Guk-Heon Choi, Duhwan Mun, Soonhung Han. Exchange of CAD Part Models
Based on the Macro-Parametric Approach. International Journal of CAD/CAM,
Vol. 2, No. 1, pp. 13~21, 2002.
P.Cignoni, C. Montani and R. Scopigno. A Comparison of Mesh Simplification
Algorithms. Computer & Graphics, Vol. 22, No. 1, pp. 37-54, 1998.
L. Kobbelt, S. Campagna, H.P. Siedel. A General Framework for Mesh
Decimation. Computer Science Department, University of Erlangen-Nurnberg.
William J. Schroeder et al, Kok Lim et al. Decimation of Triangle Meshes &
Model Simplification Using Vertex-Clustering.
J.Y.H. Fuha, W.D. Lib. Advances in collaborative CAD: the-state-of-the art.
www.macro-parametrics.org
www.tetgen.berlios.de
www.meshlab.org
ACIS Models from: http://www.opencascade.org/showroom/shapegallery/gal5/
23
References
10. Steven J. Owen. “A Survey of Unstructured Mesh Generation Technology”.
ANSYS Inc., Canonsburg, PA.
11. Jonathan Richard Shewchuk. “Triangle: Engineering a 2D Quality Mesh Generator
and Delaunay Triangulator”. School of Computer Science, Carnegie Mellon
University.
12. Steven J. Owen, David R. White, Timothy J. Tautges. “FACET-BASED
SURFACES FOR 3D MESH GENERATION”.
13. A. Ciampalini, P. Cignoni, C. Montani, R. Scopigno. Multiresolution decimation
based on global error. The Visual Computer (1997)
14. Leila De Floriani and Paola Magillo. Multiresolution Mesh Representation: Models
and Data Structures.
15. P. Alliez, G. Ucelli, C. Gotsman, and M. Attene. Recent advances in remeshing of
surfaces. State-of-the-art report, 2005.
24
Appendix
25
Neutral Modeling Command
ENTITY SOLID_Create_Protrusion_Extrude;
result_object_name : STRING;
profile_sketch
: STRING;
flip
: BOOLEAN;
start_condition
: end_type;
start_depth
: length_measure;
end_condition
: end_type;
end_depth
: length_measure;
END_ENTITY;
start_condition
start_depth
profile_sketch
end_condition
end_depth
26
Classification of Neutral Modeling Commands
No. of CC
No. of NCC
Sum
Sketch commands
30
27
57
Surface commands
17
6
23
Solid commands
22
18
40
Constraint commands
21
3
24
90
54
144
CC: Core commands
NCC: Non-core commands
27
XML Schema
Neutral
macro
schema
XML macro
schema
ENTITY SOLID_Create_Protrusion_Extrude;
result_object_name : STRING;
profile_sketch
: STRING;
flip
: BOOLEAN;
start_condition
: end_type;
start_depth
: length_measure;
end_condition
: end_type;
end_depth : length_measure;
END_ENTITY;
28
L-Block (K1)
Neutral XML
X3D
29
Y-model (K2)
Neutral XML
X3D
30
Gas Spring (K3)
Neutral XML
X3D
31
Linear Sensor (K4)
Neutral XML
X3D
32
Engine Air-Filter Housing (K5)
X3D
Neutral XML
33
Effect of Normal Tolerance on Faceting
NT = 5
NT = 10
NT = 20
NT = 40
34